Method for preparing transparent conductive silver patterns

ABSTRACT

Electrically-conductive articles are prepared to have electrically-conductive silver metal electrode grids and electrically-conductive silver connector wire patterns (BUS lines) on one or both supporting sides of a transparent substrate. The electrically-conductive silver connector wire patterns are designed with one silver main wire that comprises two or more adjacent silver micro-wires in bundled patterns. These bundled patterns and silver micro-wires are designed with specific dimensions and configurations to provide optimal fidelity (or correspondence) to the mask image used to provide such images in a silver halide emulsion layer. The electrically-conductive articles are provided by imagewise exposure, development, and fixing of corresponding silver halide-containing conductive film element precursors containing photosensitive silver halide emulsion layers. The electrically-conductive articles can be used as parts of various electronic devices including touch screen devices.

RELATED APPLICATIONS

Reference is made to the following copending and commonly assignedpatent applications, the disclosures of all of which are incorporatedherein by reference:

U.S. Ser. No. 13/751,430 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok);

U.S. Ser. No. 13/751,443 (filed Jan. 28, 2013 by Lebens, Trauemicht,Wang, and Cok);

U.S. Ser. No. 13/751,464 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok);

U.S. Ser. No. 13/751,450 (filed Jan. 28, 2013 by Lebens, Trauemicht,Wang, and Cok);

U.S. Ser. No. 13/964,453 (filed Aug. 12, 2013 by Lebens and Cok);

U.S. Ser. No. 14/66,910 (filed Jan. 29, 2014 by Kenneth Lushington);

U.S. Ser. No. 14/281,923 (filed on May 20, 2014 by Lushington, Cok, andSutton) entitled “Article with Electrically-conductive Silver ConnectorWire Pattern;”

U.S. Ser. No. 14/281,953 (filed on May 20, 2014 by Cok, Sutton, andLushington) entitled “Electrically Conductive Article with Improved BUSRegion;”

U.S. Ser. No. 14/281,968 (filed on May 20, 2014 by Youngblood and Lowe)entitled “Method for Providing Conductive Silver Film Elements;”

U.S. Ser. No. 14/281,977 (filed on May 20, 2014 by Youngblood and Lowe)entitled “Silver Halide Developing Solution;”

U.S. Ser. No. 14/281,984 (filed on May 20, 2014 by Youngblood and Lowe)entitled “Silver Halide Solution Physical Developing Solution.”

FIELD OF THE INVENTION

This invention relates to a method for preparing transparentelectrically-conductive articles having electrically-conductive silvermetal electrode grids and electrically-conductive silver connector wirepatterns from conductive film element precursors that have aphotosensitive silver halide emulsion layer on one or both sides of atransparent substrate. The electrically-conductive articles havespecifically arranged electrically-conductive silver metal (fine wire)grids in a touch region and electrically-conductive silver connectorwire patterns, on one or both sides of the transparent substrate.

BACKGROUND OF THE INVENTION

Rapid advances are occurring in various electronic devices especiallydisplay devices that are used for various communicational, financial,and archival purposes. For such uses as touch screen panels,electrochromic devices, light-emitting diodes, field-effect transistors,and liquid-crystal displays, electrically-conductive films are essentialand considerable efforts are being made in the industry to improve theproperties of those electrically-conductive films and particularly toimprove metal grid or line conductivity and to provide as muchcorrespondence between mask design with resulting user metal patterns.

Electrically-conductive articles used in various electronic devicesincluding touch screens in electronic, optical, sensory, and diagnosticdevices including but not limited to telephones, computing devices, andother display devices have been designed to respond to touch by a humanfingertip or mechanical stylus.

There is a particular need to provide touch screen displays and devicesthat contain improved electrically-conductive film elements. Currently,touch screen displays use Indium Tin Oxide (ITO) coatings to createarrays of capacitive areas used to distinguish multiple points ofcontacts. ITO coatings have significant disadvantages and efforts arebeing made to replace their use in various electronic devices.

Silver is an ideal conductor having an electrical conductivity 50 to 100times greater than ITO and is being explored for this purpose. Unlikemost metal oxides, silver oxide is still reasonably conductive and thisreduces the problem of making reliable electrical connections. Silver isused in many commercial applications and is available from numeroussources. It is highly desirable to make electrically-conductive filmelements using silver as the source of conductivity, but it requiresconsiderable development to obtain optimal properties.

In known printed circuit board (PCB) and integrated circuit manufactureprocesses, the preferred means for mass manufacture is to print acircuit directly from a master article onto a suitable substrate, tocreate a copy of the circuit image on a suitable PCB photosensitivefilm, or to directly laser-write a master circuit image (or inversepattern) onto the PCB photosensitive film. The imaged PCB photosensitivefilm is then used as a “mask” for imaging multiple copies onto one ormore photoresist-coated substrates.

An essential feature of these methods is that the PCB photosensitivefilm and photoresist compositions are optimized in formulation anddevelopment so that the imaged copies are as faithful a representationof the master image as possible with respect to circuit dimensions andproperties. This property is sometimes referred to as “fidelity” (or“correspondence”) and the worse the fidelity, the poorer the performanceof the resulting copies. However, in mass production of these electricalcircuits having designed patterns with very fine dimensional features,there are a number of compositional and operational (for example,chemical processing) conditions that naturally work against fidelity, ormaking faithful reproductions of the master circuit image.

This is particularly true when silver halide is used for making themultiple copies of a master circuit pattern intended for use astransparent conductive patterns. For example, development of exposedsilver halide using strong developers intended to achieve highconductivity, and the high level of silver in the photosensitivecoatings for the same purpose, can lead to very large dimensionaldifferences between the master circuit image and copies made thereofusing various mask elements. In addition, this lack of faithfulreproduction of the dimensions in the master circuit image is stronglyinfluenced by the dimensional scale of the circuitry images that arebeing reproduced. Thus, smaller features in the master circuit imagebecome larger and the larger features in the master circuit image becomesmaller. These objectionable changes in the features from “master tocopy” result in reduced conductivity in the resulting copy patterns andoverall poorer performance in the electrical devices in which they areincorporated.

It requires considerable research and development effort to determinethe various causes of the lack of fidelity between master circuit imageand copies, especially when photosensitive silver halide is used forthis process. There are numerous publications relating to usingphotosensitive silver halide in this manner, but none that addresses thenoted problem.

For example, U.S. Patent Application Publication 2011/0308846 (Ichiki)describes the preparation of electrically-conductive films formed byreducing a silver halide image in electrically-conductive networks withsilver wire sizes less than 10 μm, which electrically-conductive filmscan be used to form touch panels in displays. In addition, improvementshave been proposed for providing conductive patterns usingphotosensitive silver salt compositions such as silver halide emulsionsas described for example in U.S. Pat. No. 8,012,676 (Yoshiki et al.).

Recently designed improved electrically-conductive articles are preparedfrom photosensitive silver halide precursor articles as described forexample in copending and commonly assigned U.S. Ser. No. 14/66,910(noted above).

Electrically-conductive silver articles have been described for use intouch screen panels that have electrically-conductive silver gridpatterns on both sides of a transparent substrate, for example as inU.S. Patent Application Publications 2011/0289771 (Kuriki) and2011/0308846 (Ichiki).

However, the mere presence of electrically-conductive silver gridpatterns on one or both sides of the transparent substrate is notsufficient to provide response that is needed for sensing touch forvarious electronic devices. The electrically-conductive grid patternsmust be connected in some manner to each other and to suitableelectronic components and software in the devices so that desiredfunctions can be accomplished in response to a touch from a finger orstylus. Thus, the electrically-conductive articles are also designedwith conductive “BUS” lines or conductive silver connecting wiring thatis outside the electrically-conductive electrode regions (“touchregions”) designed for touching. In some embodiments, suchelectrically-conductive articles have “sensitive regions” and “terminalwiring regions” on one or both sides of the transparent substrate. Onerepresentation of such an electrically-conductive article is shown inFIG. 8 of U.S. Patent Application 2011/0289771 (noted above).

Normally, the electrically-conductive wiring in theelectrically-conductive article is not designed for high transparency orsensitivity to touch. The electrically-conductive wiring will likelyhave different conductivity and dimensions compared to theelectrically-conductive grid patterns in what are known as the“sensitive regions” of the electrically-conductive article. Thesedifferences further make it harder to achieve desired fidelity of amaster circuit image and copies made therefrom.

Thus, there is a need for a means for providing transparentelectrically-conductive articles that have both conductive silver gridsin touch sensitive regions as well as electrically-conductive silverwiring that are as close to being reproductions to the master circuitimage as possible. The present invention addresses these problems.

SUMMARY OF THE INVENTION

The present invention addresses these problems by providing a conductivearticle using photosensitive black-and-white silver halide emulsions andblack-and-white silver halide processing chemistry, the method of thisinvention comprising:

imagewise exposing a conductive film element precursor that comprises: atransparent substrate comprising a first supporting side and an opposingsecond supporting side; and a photosensitive silver halide emulsionlayer on at least the first supporting side, to radiation to provide, inthe photosensitive silver halide emulsion layer on at least the firstsupporting side: (a) a latent electrically-conductive silver metalelectrode grid, (b) a latent electrically-conductive silver connectorwire pattern different from the latent electrically-conductive silvermetal electrode grid, and optionally, (c) transparent regions outside ofboth the latent electrically-conductive silver metal electrode grid andthe latent electrically-conductive silver connector wire pattern; and

processing the latent electrically-conductive silver metal electrodegrid and latent electrically-conductive silver connector wire patternusing at least solution physical development and silver halide fixing,to provide: (a) an electrically-conductive silver metal electrode gridfrom the latent electrically-conductive silver metal electrode grid, (b)an electrically-conductive silver connector wire pattern from the latentelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the electrically-conductivesilver metal electrode grid and the electrically-conductive silver wireconnector pattern,

-   -   wherein:    -   (i) the electrically-conductive silver connector wire pattern        comprises at least one silver main wire that comprises two or        more silver micro-wires that are electrically connected to a        silver end wire at an end of the at least one silver main wire,        the two or more silver micro-wires and the silver end wire in        the at least one silver main wire forming a bundled pattern;    -   (ii) the average length of each silver micro-wire is at least 1        mm;    -   (iii) the ratio of the average width of each silver micro-wire        to the average distance between two adjacent silver micro-wires        in each bundled pattern is at least 0.5:1 but less than 2:1;    -   (iv) the electrically-conductive silver connector wire pattern        has an integrated transmittance of less than 68%; and    -   (v) for each silver micro-wire, the ratio of maximum height to        minimum height is at least 1.05:1.

In many embodiments of this method, the conductive film elementprecursor further comprises a photosensitive silver halide emulsionlayer disposed on the opposing second supporting side of the transparentsubstrate, and

the method further comprises:

imagewise exposing the photosensitive silver halide emulsion layer onthe opposing second supporting side to provide (a) an opposing latentelectrically-conductive silver metal electrode grid, (b) an opposinglatent electrically-conductive silver connector wire pattern differentfrom the opposing latent electrically-conductive silver metal electrodegrid, and optionally, (c) transparent regions outside of both the latentelectrically-conductive silver metal electrode grid and the opposinglatent electrically-conductive silver connector wire pattern; and

processing the opposing latent electrically-conductive silver metalelectrode grid and the opposing latent electrically-conductive silverconnector wire pattern using at least solution physical development andsilver halide fixing, to provide: (a) an opposingelectrically-conductive silver metal electrode grid from the opposinglatent electrically-conductive silver metal electrode grid, (b) anopposing electrically-conductive silver connector wire pattern from theopposing latent electrically-conductive silver connector wire pattern,and optionally, (c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern,

-   -   wherein, on the opposing second supporting side:    -   (i) the opposing electrically-conductive silver connector wire        pattern comprises at least one silver main wire that comprises        two or more silver micro-wires that are electrically connected        to a silver end wire at an end of the at least one silver main        wire, the two or more silver micro-wires and the silver end wire        in the at least one silver main wire forming a bundled pattern;    -   (ii) the average length of each silver micro-wire is at least 1        mm;    -   (iii) the ratio of the average width of each silver micro-wire        to the average distance between two adjacent silver micro-wires        in each bundled pattern is at least 0.5:1 but less than 2:1;    -   (iv) the opposing electrically conductive silver connector wire        pattern has an integrated transmittance of less than 68%; and    -   (v) for each silver micro-wire, the ratio of maximum height to        minimum height is at least 1.05:1.

Thus, the method of the present invention provides anelectrically-conductive article that has both electrically-conductivesilver metal electrode grids (for the “touch sensitive” or “touch”regions) and electrically-conductive silver connector wire patterns(also identified as BUS lines, BUS regions, or simply electrodeconnector regions) with improved matching (correspondence or fidelity)of the images of these regions to the images in the original maskelement through which imagewise exposure occurs.

The advantages are achieved for the electrically-conductive silver wirepatterns in the electrode connector regions by arranging at least onesilver main wire (for example, two or more silver main wires) intobundled patterns of two or more silver micro-wires and various silverend wires for each bundled pattern. In addition, adjacent silvermicro-wires in the bundled pattern can be arranged with bothelectrically-connecting silver cross-wires and silver end wires. Thebundled patterns and silver micro-wires are obtained from exposure andprocessing with specific dimensions, spacing, and conductive propertiesfor optimal performance in touch screen devices. The bundled patterns ofsilver main wires and silver micro-wires increase electricalconductivity, manufacturability, and robustness even in the presence ofsome manufacturing defects. In other words, the possible effects ofmanufacturing defects or inconsistencies are at least reduced using thepresent invention.

Known methods for preparing electrically-conductive articles typicallycause the formation of continuous, solid, and substantially flatconductive lines and attempt to make maximum use of the available spaceon a transparent substrate. However, it has been found that the use ofsolution physical development with imagewise exposed silver halideemulsions does not readily allow the formation of such continuous,solid, and substantially flat conductive lines having desired electricalconductivity and lower resistance. Hence, known silver halide films andprocessing methods are not useful for this purpose, and would not teachor motivate a skilled worker to find and use the method of the presentinvention. In particular, methods of the art that include silver halidedevelopment but do not include solution physical development, or whichinclude known plating methods in which the deposited metals (or metalions) come from an external source such as a solution, can formcontinuous, solid, and flat conductive lines and therefore do notsuggest the methods of the present invention.

In contrast to known methods, the electrically-conductive articlesprovided by the present invention exhibit improved electricalconductivity from the presence of unique silver micro-wire bundledpatterns. In one useful embodiment, the silver-micro-wires have anaverage width of at least 5 μm and up to and including 20 μm. Thus, themethod described herein provides electrically-conductive articles havinghighly electrically-conductive silver connector wire patterns withoutrequiring the formation of continuous, solid, and substantially flatconductive lines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an electrically-conductive silverconnector wire pattern shown on one side of a transparent substrate,which electrically-conductive silver connector wire pattern can beincorporated into or part of an electrically-conductive article preparedusing this invention.

FIG. 2 is a schematic cross-sectional view of an electrically-conductivearticle prepared according to the present invention.

FIG. 3A is a schematic cross-sectional view of a conductive film elementprecursor comprising a portion of a photosensitive silver halideemulsion layer disposed on a transparent substrate, which portion ofphotosensitive silver halide emulsion layer comprises non-developedphotosensitive silver halide grains.

FIG. 3B is a schematic cross-sectional view of a conductive film elementprecursor comprising developed photosensitive silver halide grains in arepresentative silver micro-wire disposed on a transparent substrate,which silver micro-wire can be obtained from the portion ofphotosensitive silver halide emulsion layer shown in FIG. 3A.

FIGS. 4 and 5 are schematic illustrations of electrically-conductivesilver connector wire patterns shown on one side of a transparentsubstrate, showing both silver end wires and different arrangements ofsilver cross-wires in multiple bundled patterns.

FIGS. 6 to 9 are flow charts showing options for formingelectrically-conductive articles from single-sided or duplex conductivefilm element precursors.

FIG. 10 is a schematic cross-sectional view of a silver micro-wire on atransparent substrate, which silver micro-wire has a maximum heightessentially at its center.

FIG. 11 is a schematic cross-sectional view of a silver micro-wire on atransparent substrate, which silver micro-wire has a maximum heightcloser to its outer edge than its center.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion is directed to various embodiments of thepresent invention and while some embodiments can be more desirable forspecific uses, the disclosed embodiments should not be interpreted orotherwise considered to be limiting the scope of the present invention,as claimed below. Thus, one skilled in the art should understand thatthe following disclosure and illustrative FIGS. have broader applicationthan is explicitly described and the discussion or illustration of anembodiment is not intended to limit the scope of the present invention.

DEFINITIONS

As used herein to define various components and structures of theconductive film element precursors including photosensitive silverhalide emulsion layers and processing solutions, unless otherwiseindicated, the singular forms “a”, “an”, and “the” are intended toinclude one or more of the components (that is, including pluralityreferents).

Each term that is not explicitly defined in the present application isto be understood to have a meaning that is commonly accepted by thoseskilled in the art. If the construction of a term would render itmeaningless or essentially meaningless in its context, the termdefinition should be taken from a standard dictionary.

The use of numerical values in the various ranges specified herein,unless otherwise expressly indicated otherwise, are considered to beapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about.” In this manner,slight variations above and below the stated ranges can be used toachieve substantially the same results as the values within the ranges.In addition, the disclosure of these ranges is intended as a continuousrange including every value between the minimum and maximum values.

Unless otherwise indicated, the term “weight %” refers to the amount ofa component or material based on the total solids of a composition,formulation, solution, or the % of the dry weight of a layer. Unlessotherwise indicated, the percentages can be the same for either a drylayer or pattern, or for the total solids of the formulation orcomposition used to make that layer or pattern.

Unless otherwise indicated, a “conductive film element precursor” and“precursor” are meant to be the same thing and to refer to an articleused in the practice of the method of this invention to provide anelectrically-conductive film element (or electrically-conductivearticle). Such precursors therefore comprise a “silver precursormaterial” (such as a silver halide) that can be converted to conductivesilver metal particles (for example by reduction). Much of thediscussion about the precursors is equally applicable to the conductivearticles as most of the components and structure are not changed whensilver cations are converted to silver metal particles. Thus, unlessotherwise indicated, the discussion of transparent substrates,hydrophilic binders and colloids, and other addenda in photosensitivesilver halide emulsion layers, any hydrophilic overcoats, and any othercomponents or layers for the precursors are also intended to describethe components of the resulting electrically-conductive articles.

Unless otherwise indicated, the terms “electrically-conductive filmelement” and “electrically-conductive article” are intended to mean thesame thing. They refer to the materials containing theelectrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns disposed oneither or both supporting sides of a suitable transparent substrate.Other components of the electrically-conductive article are describedbelow.

The term “first” refers to the layers on one (first) supporting side ofthe transparent substrate and the term “second” refers to the layers onthe opposing (opposite) second supporting side of the transparentsubstrate. Each supporting side of the transparent substrate can beequally useful and the term “first” does not necessarily mean that oneside is the primary or better supporting side of the precursor orelectrically-conductive article.

The terms “duplex” and “two-sided” are used herein in reference toprecursors and electrically-conductive articles having the describedlayers and electrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns on bothsupporting sides of the transparent substrate. Unless otherwiseindicated herein, the relationships and compositions of the variouslayers can be the same or different on both supporting sides of thetransparent substrate.

ESD refers to “equivalent spherical diameter” and is a term used in thephotographic art to define the size of particles such as silver halidegrains. Particle size of silver halide grains as expressed in grain ESDcan be readily determined using disc centrifuge instrumentation.

Unless otherwise indicated, “black-and-white” refers to silver-formingblack-and-white materials and formulations, and not chromogenicblack-and-white materials and formulations.

In most embodiments, the conductive film element precursors and theresulting electrically-conductive articles, including the transparentsubstrate and all accompanying layers, electrically-conductive silvermetal electrode grids, and transparent regions on one or both supportingsides, are considered transparent meaning that its integratedtransmittance over the noted visible region of the electromagneticspectrum (for example from 410 nm to 700 nm) is 70% or more, or morelikely at least 85% or even 90% or more, as measured for example using aspectrophotometer and known techniques. Thus, the touch regions in theresulting electrically-conductive articles will have this highintegrated transmittance. However, the electrode connector regionscontaining the electrically-conductive silver connector wire patternsare generally much less transparent than the rest of theelectrically-conductive articles and generally have an integratedtransmittance of less than 68%, or less than 50%, or even less than 40%using the same equipment and procedures noted above.

Alternatively, the integrated transmittance can be associated with thecalculated percentage of the transparent substrate area that is notcovered by either the electrically-conductive silver metal electrodegrid in the touch region or by the electrically-connected silverconnector wire pattern in the electrode connector region.

In defining various dimensions of the silver main wires and silvermicro-wires provided in the conductive articles, each dimension“average” is determined from at least 5 measurements of the specificdimension using appropriate measurement techniques and equipment thatwould be known to one skilled in the art.

Unless otherwise indicated, the terms “electrode connector regions,”“BUS lines,” and “BUS regions” mean the same thing.

Uses

The conductive film element precursors described herein can be used toform electrically-conductive articles that have various uses. Forexample, the electrically-conductive articles can be used as devicesthemselves or they can be used as components in devices having a varietyof applications including but not limited to, electronic, optical,sensory, and diagnostic uses. In particular, it is desired to use theconductive film element precursors to provide highlyelectrically-conductive silver metal electrode grids andelectrically-conductive silver metal connector wire patterns comprisingsilver metal lines having suitable height, width, and conductivity foruse in touch screen displays or as components of touch-screen devices.Such electronic and optical devices and components include but are notlimited to, radio frequency tags (RFID), sensors, touch-screen displays,and memory and back-panels for displays.

Conductive Film Element Precursors

The conductive film element precursors used in the practice of thisinvention comprise photosensitive silver halide(s) but they do notgenerally contain chemistry sufficient to provide color photographicimages. Thus, these “precursors” are considered to be black-and-whitephotosensitive materials forming metallic silver images followingexposure and development, and are non-color image-forming.

The precursors and the resulting electrically-conductive articles,including the transparent substrate and all accompanying layers on oneor both supporting sides, are considered transparent in the touchregions in which the electrically-conductive silver metal electrodegrids are formed, and other transparent regions outside theelectrically-conductive silver metal electrode grids and theelectrically-conductive silver connector wire pattern, meaning that theintegrated transmittance over the visible region of the electromagneticspectrum (for example from 410 nm to 700 nm) through the entireelectrically-conductive article in these touch regions and othertransparent regions is 70% or more, or more likely at least 85%, or even90% or more. Integrated transmittance is measured as described above.

However, the electrode connector regions of the processed photosensitivesilver halide emulsion layers that are used to provide theelectrically-conductive silver connector wire patterns are lesstransparent due to the higher coverage of silver metal formed in thoseelectrode connector regions. For example, such electrode connectorregions comprised of electrically-conductive silver connector wirepatterns generally have an integrated transmittance of less than 68%, orless than 50%, or even less than 40%.

The precursors can be formed by providing a non-color (that is, silverimage-forming black-and-white) photosensitive silver halide emulsionlayer on one or both supporting sides (or planar sides as opposed tonon-supporting edges) of a suitable transparent substrate in a suitablemanner. Each photosensitive layer comprises a silver halide, or amixture of silver halides, at a suitable silver coverage, such as atotal silver coverage of at least 2500 mg Ag/m², or at least 3500 mgAg/m² but usually less than 5000 mg Ag/m², for example up to andincluding 4950 mg Ag/m². However, higher amounts of silver coverage canbe used as would be known in the art. Thus, each photosensitive layerhas sufficient silver halide intrinsic or added spectral sensitizationto be photosensitive to preselected imaging irradiation (describedbelow). The photosensitive layers can be the same or different incomposition and spectral sensitization on the opposing supporting sidesof the transparent substrate.

The one or more silver halides are dispersed within one or more suitablehydrophilic binders or colloids as described below.

Such precursors are therefore treated (or processed) in such a manner asto convert the silver cations into silver metal particles (such as byreduction), and this treated precursor can then become anelectrically-conductive article according to the present invention.

The precursors can have one essential layer on each supporting side ofthe transparent substrate, which essential layer is a photosensitivesilver halide emulsion layer. This essential layer can be disposed ononly one supporting side of the transparent substrate, but in manyduplex embodiments, it is disposed on both first supporting and opposingsecond supporting sides of the transparent substrate. Optional layers,such as hydrophilic overcoats and filter dye layers can also be presenton either or both supporting sides and are described below but they arenot essential to achieve the desired advantages of the presentinvention.

Transparent Substrates:

The choice of a transparent substrate generally depends upon theintended utility of the resulting electrically-conductive article suchthat the conductive article can be fabricated in a suitable manner for apredetermined device. The transparent substrate can be rigid orflexible, and generally has an integrated transmittance of at least 90%and generally at least 95% over the visible region of theelectromagnetic spectrum (for example at least 410 nm and up to andincluding 700 nm). Integrated transmittance can be determined using aspectrophotometer and known procedures as described above.

Suitable transparent substrates include but are not limited to, glass,glass-reinforced epoxy laminates, cellulose triacetate, acrylic esters,polycarbonates, adhesive-coated polymer transparent substrates,polyester films, and transparent composite materials. Suitabletransparent polymers for use as transparent polymer substrates includebut are not limited to, polyethylene and other polyolefins, polyesterssuch as polyethylene terephthalate (PET), polyethylene naphthalate(PEN), poly-1,4-cyclohexanedimethylene terephthalate, poly(butyleneterephthalate), and copolymers thereof, polypropylenes, polyvinylacetates, polyurethanes, polyamides, polyimides, polysulfones,polycarbonates, and mixtures thereof. Other useful transparentsubstrates can be composed of cellulose derivatives such as a celluloseester, cellulose triacetate, cellulose diacetate, cellulose acetatepropionate, cellulose acetate butyrate, polyacrylates, polyether imides,and mixtures thereof.

Transparent polymeric substrates can also comprise two or more layers ofthe same or different polymeric composition so that the compositetransparent substrate (or laminate) has the same or different layerrefractive properties. The transparent substrate can be treated oneither or both supporting sides to improve adhesion of a photosensitivesilver halide emulsion or underlying layer. For example, the transparentsubstrate can be coated with a polymer adhesive layer, can be chemicallytreated, or subjected to a corona treatment, on one or both supportingsides.

Commercially available oriented and non-oriented transparent polymerfilms, such as biaxially-oriented polypropylene or polyester, can beused. Such transparent substrates can contain pigments, air voids orfoam voids as long as desired integrated transmittance is obtained. Thetransparent substrate can also comprise microporous materials such aspolyethylene polymer-containing material sold by PPG Industries, Inc.,Pittsburgh, Pa. under the trade name of Teslin®, Tyvek® synthetic paper(DuPont Corp.). The transparent substrate also can be voided, whichmeans it contains voids formed as interstitial voids using added solidand liquid materials, or “voids” containing a gas. Some commercialmicrovoided products are commercially available as 350K18 fromExxonMobil and KTS-107 (from HSI, South Korea).

Biaxially-oriented sheets, while described as having at least one layer,can also be provided with additional layers that can serve to change theoptical or other properties of the biaxially-oriented sheet. Such layersmight contain tints, antistatic or conductive materials, or slip agents.The biaxially-oriented extrusion can be carried out with as many as 10layers if desired, made with layers of the same polymeric material, orwith layers having different polymeric composition.

Flexible transparent substrates for the manufacture of flexibleelectronic devices or touch screen components facilitate rapidroll-to-roll manufacture. Estar® poly(ethylene terephthalate) films andcellulose triacetate films are particularly useful materials for makingflexible transparent substrates.

The transparent substrate used in the precursors can have a thickness ofat least 20 μm and up to and including 300 μm or typically at least 75μm and up to and including 200 μm. Antioxidants, brightening agents,antistatic or conductive agents, plasticizers, and other known additivescan be incorporated into the transparent substrate, if desired, inamounts that would be readily apparent to one skilled in the art as longas desired integrated transmittance is preserved.

Photosensitive Silver Halide Emulsion Layers:

The essential silver halide(s) in these layers comprise silver cationsof one or more silver halides that can be converted into silver metalparticles according to desired patterns upon imagewise exposure of eachphotosensitive silver halide emulsion layer. Such exposure is generallyachieved by imaging through a mask element that is designed withpredetermined patterns for both the electrically-conductive silver metalelectrode grid and the electrically-conductive silver connector wirepattern. The latent image(s) provided by this exposure can then bedeveloped into desired silver metal image(s) using known silverdevelopment procedures and chemistry (described below). The silverhalide (or combination of silver halides) is photosensitive, meaningthat radiation from UV to visible light (for example, of at least 200 nmand up to and including 750 nm radiation) is generally used to convertsilver cations to silver metal particles in a latent image. In someembodiments, the silver halide is present in combination with athermally-sensitive silver salt (such as silver behenate) and thephotosensitive silver halide emulsion layer can be both photosensitiveand thermally sensitive (that is, sensitive to thermal imaging energysuch as infrared radiation).

The useful photosensitive silver halides can be, for example, silverchloride, silver bromide, silver chlorobromoiodide, silverbromochloroiodide, silver chlorobromide, silver bromochloride, or silverbromoiodide that are prepared as individual compositions (or emulsions).The various halides are listed in the silver halide name in descendingorder of halide amount. In addition, individual silver halide emulsionscan be prepared and mixed to form a mixture of silver halide emulsionsthat are used on the same or different supporting sides of thetransparent substrate. In general, the useful silver halides comprise upto and including 100 mol % of chloride or up to and including 100 mol %of bromide, and up to and including 5 mol % iodide, all based on totalsilver. These silver halides are generally known as “high chloride” or“high bromide” silver halides and can be used to form “high chloride,”or “high bromide” emulsions, respectively.

The silver halide grains used in each photosensitive silver halideemulsion layer generally have an ESD of at least 30 nm and up to andincluding 300 nm, or more likely at least 50 nm and up to and including200 nm.

The coverage of total silver in each photosensitive silver halideemulsion layer is desirably at least 2500 mg Ag/m² and typically atleast 3500 mg Ag/m² and can be less than 5000 mg Ag/m², although higheramounts can be used.

The dry thickness of each photosensitive silver halide emulsion layer isgenerally at least 0.5 μm and up to and including 12 μm, andparticularly at least 0.5 μm and up to and including 7 μm.

The final dry photosensitive silver halide emulsion layer can be made upof one or more individually coated photosensitive silver halide emulsionsub-layers that can be applied using the same or different silver halideemulsion formulations. Each sub-layer can be composed of the same ordifferent silver halide(s), hydrophilic binders or colloids, andaddenda. The photosensitive silver halide emulsion sub-layers can havethe same or different amount of silver content.

The photosensitive silver halide(s) used in the photosensitive silverhalide emulsion layer on the first supporting side can be the same ordifferent from the photosensitive silver halide(s) used in the opposingsecond supporting side photosensitive silver halide emulsion layer.

The photosensitive silver halide grains (and any addenda associatedtherewith as described below) are dispersed (generally uniformly) in oneor more suitable hydrophilic binders or colloids to form a hydrophilicsilver halide emulsion. Examples of such hydrophilic binders or colloidsinclude but are not limited to, gelatin and gelatin derivatives,polyvinyl alcohol (PVA), poly(vinyl pyrrolidone) (PVP), casein, andmixtures thereof. Suitable hydrophilic colloids and vinyl polymers andcopolymers are also described in Section IX of Research Disclosure Item36544, September 1994 that is published by Kenneth Mason Publications,Emsworth, Hants, PO10 7DQ, UK. A particularly useful hydrophilic colloidis gelatin or a gelatin derivative of which several are known in theart.

The amount of hydrophilic binder or colloid in each photosensitivesilver halide emulsion layer can be adapted to the particular drythickness that is desired as well as the amount of silver halide that isincorporated. It can also be adapted to meet desired dispersibility,swelling, and layer adhesion to the transparent substrate. The amount ofhydrophilic binder or colloid is generally controlled to maximize theconductivity of the resulting silver metal particles in the conductivearticles.

In general, the one or more hydrophilic binders or colloids are presentin an amount of at least 10 weight % and up to and including 95 weight%, or more likely at least 10 weight % and up to and including 50 weight%, all based on the total solids in the dry photosensitive silver halideemulsion layer.

Some useful photosensitive silver halide emulsion layer composition havea relatively high silver ion/hydrophilic binder (for example, gelatin)weight (or volume) ratio. For example, a particularly useful weightratio of silver ions (and eventually silver metal) to hydrophilic binderor colloid such as gelatin (or its derivative) is at least 0.1:1, oreven at least 1.5:1 and up to and including 10:1. A particularly usefulweight ratio of silver ions to the hydrophilic binder or colloid can beat least 2:1 and up to and including 5:1. Other weight ratios can bereadily adapted for a particular use and dry layer thickness.Particularly useful silver ion/hydrophilic binder (gelatin) volume ratiois less than 0.5:1 or even less than 0.35:1.

The hydrophilic binder or colloid can be used in combination with one ormore hardeners designed to harden the particular hydrophilic binder suchas gelatin. Particularly useful hardeners for gelatin and gelatinderivatives include but are not limited to, non-polymeric vinyl-sulfonessuch as bis(vinyl-sulfonyl) methane (BVSM), bis(vinyl-sulfonyl methyl)ether (BVSME), and 1,2-bis(vinyl-sulfonyl acetamide)ethane (BVSAE).Mixtures of hardeners can be used if desired. The hardeners can beincorporated into each photosensitive silver halide emulsion layer inany suitable amount that would be readily apparent to one skilled in theart.

In general, each photosensitive silver halide emulsion layer can behardened so that it has swell ratio of at least 150% but less than 300%as determined by optical microscopy of element cross-sections, and theswell ratio can be provided by use of appropriate amounts of hardenerswithin the photosensitive silver halide emulsion layer, or hardenerswithin various processing solutions (described below).

If desired, the useful silver halides described above can be sensitizedto any suitable wavelength of exposing radiation. Organic sensitizingdyes can be used, but it can be advantageous to sensitize the silversalt to the UV portion of the electromagnetic spectrum without usingvisible light sensitizing dyes to avoid unwanted dye stains if theelectrically-conductive article containing the silver metal particles isintended to be transparent. Alternatively, the silver halides can beused without spectral sensitization beyond their intrinsic spectralsensitivities.

Non-limiting examples of addenda that can be included with the silverhalides, including chemical and spectral sensitizers, filter dyes,organic solvents, thickeners, dopants, emulsifiers, surfactants,stabilizers, hardeners, and antifoggants are described in ResearchDisclosure Item 36544, September 1994 and the many publicationsidentified therein. Such materials are well known in the art and itwould not be difficult for a skilled artisan to formulate or use suchcomponents for purposes described herein. Some useful silver saltemulsions are described, for example in U.S. Pat. No. 7,351,523(Grzeskowiak), U.S. Pat. No. 5,589,318, and U.S. Pat. No. 5,512,415(both to Dale et al.).

Useful silver halide emulsions containing silver halide grains that canbe reduced to silver metal particles can be prepared by any suitablemethod of grain growth, for example, by using a balanced double run ofsilver nitrate and salt solutions using a feedback system designed tomaintain the silver ion concentration in the growth reactor. Knowndopants can be introduced uniformly from start to finish ofprecipitation or can be structured into regions or bands within thesilver halide grains. Useful dopants include but are not limited to,osmium dopants, ruthenium dopants, iron dopants, rhodium dopants,iridium dopants, and cyanoruthenate dopants. A combination of osmium andiridium dopants such as a combination of osmium nitrosyl pentachlorideand iridium dopant is useful. Such complexes can be alternativelyutilized as grain surface modifiers in the manner described in U.S. Pat.No. 5,385,817 (Bell). Chemical sensitization can be carried out by anyof the known silver halide chemical sensitization methods, for exampleusing thiosulfate or another labile sulfur compound, alone or incombination with gold complexes.

Useful silver halide grains can be rounded cubic, octahedral, roundedoctahedral, polymorphic, tabular, or thin tabular emulsion grains. Suchsilver halide grains can be regular untwinned, regular twinned, orirregular twinned with cubic or octahedral faces. In one embodiment, thesilver halide grains can be rounded cubic having an ESD of less than 0.5μm and at least 0.05 μm.

Antifoggants and stabilizers can be added to give the silver halideemulsion the desired sensitivity, if appropriate. Useful antifoggantsinclude, for example, azaindenes such as tetraazaindenes, tetrazoles,benzotriazoles, imidazoles and benzimidazoles. Specific antifoggantsthat can be used include 6-methyl-1,3,3a,7-tetraazaindene,1-(3-acetamidophenyl)-5-mercaptotetrazole, 6-nitrobenzimidazole,2-methylbenzimidazole, and benzotriazole, individually or incombination.

The essential silver halide grains and hydrophilic binders or colloids,and optional addenda can be formulated and coated as a silver halideemulsion using suitable emulsion solvents including water andwater-miscible organic solvents. For example, useful solvents for makingthe silver halide emulsion or coating formulation can be water, analcohol such as methanol, a ketone such as acetone, an amide such asformamide, a sulfoxide such as dimethyl sulfoxide, an ester such asethyl acetate, liquid or low molecular weight poly(vinyl alcohol), or anether, or combinations of these solvents. The amount of one or moresolvents used to prepare the silver halide emulsions can be at least 30weight and up to and including 50 weight % of the total formulationweight. Such coating formulations can be prepared using any of thephotographic emulsion making procedures that are known in the art.

Hydrophilic Overcoats

While the photosensitive silver halide emulsion layer, on either or bothsupporting sides of the transparent substrate, can be the outermostlayer in the precursor, in many embodiments, there can be a hydrophilicovercoat disposed over each photosensitive silver halide emulsion layer.This hydrophilic overcoat can be the outermost layer in the precursor(that is, there are no layers purposely placed over it on either or bothsupporting sides of the transparent substrate). If both supporting sidesof the transparent substrate comprise a photosensitive silver halidelayer, then a hydrophilic overcoat can be present on both supportingsides of the transparent substrate. Thus, a first hydrophilic overcoatis disposed over the first photosensitive silver halide emulsion layer,and a second hydrophilic overcoat is disposed over a secondphotosensitive silver halide emulsion layer on the opposing secondsupporting side of the transparent substrate. In most embodiments, eachhydrophilic overcoat is directly disposed on each photosensitive silverhalide emulsion layer, meaning that there are no intervening layers onthe supporting sides of the transparent substrate. The chemicalcompositions and dry thickness of these hydrophilic overcoats can be thesame or different, but in most embodiments they have essentially thesame chemical composition and dry thickness on both supporting sides ofthe transparent substrate.

In some embodiments, each hydrophilic overcoat (first or second, orboth) comprises one or more silver halides in the same or differentamount so as to provide silver metal particles after exposure andprocessing, in an amount of at least 5 mg Ag/m² and up to and including150 mg Ag/m², or at least 5 mg Ag/m² and up to and including 75 mgAg/m². When present, the one or more silver halides in each hydrophilicovercoat can have a grain ESD of at least 100 nm and up to and including1000 nm, or at least 150 nm and up to and including 600 nm. In someembodiments, the one or more silver halides in each hydrophilic overcoathave a grain ESD that is larger than the grain ESD of the silver halidein the non-color hydrophilic photosensitive layer over which it isdisposed. In various embodiments, the silver halide(s) in eachhydrophilic overcoat comprises up to 100 mol % bromide or up to 100 mol% chloride, and up to and including 3 mol % iodide, all molar amountsbased on total silver content. In other embodiments, the silverhalide(s) in each hydrophilic overcoat comprises more chloride than thesilver halide in the non-color hydrophilic photosensitive layer overwhich it is disposed. This relationship can be the same or different onboth supporting sides of the transparent substrate in the “duplex”conductive film element precursors.

When present, the silver halide is dispersed (generally uniformly)within one or more hydrophilic binders or colloids in each hydrophilicovercoat, which hydrophilic binders or colloids include those describedabove for the non-color hydrophilic photosensitive layers. In manyembodiments, the same hydrophilic binders or colloids can be used in allof the layers of the precursor. However, different hydrophilic bindersor colloids can be used in the various layers, and on either or bothsupporting sides of the transparent substrate. The amount of one or morehydrophilic binders or colloids in each hydrophilic overcoat is the sameor different and generally at least 50 weight % and up to and including100 weight %, or typically at least 75 weight % and up to and including98 weight %, all based on total hydrophilic overcoat dry weight.

In some embodiments, the hydrophilic overcoat can further comprise oneor more radiation absorbers such as UV radiation absorbers in an amountof at least 5 mg/m² and up to and including 100 mg/m². Such UV radiationabsorbers can be “immobilized” meaning that they do not readily diffuseout of the hydrophilic overcoat.

The same hydrophilic binders or colloids are used if no silver halide ispresent, and in such embodiments, the hydrophilic binders or colloidscan comprise up to and including 100 weight % of the total hydrophilicovercoat dry weight.

Each hydrophilic overcoat can also comprise one or more hardeners for ahydrophilic binder or colloid (such as gelatin or a gelatin derivative).Useful hardeners are described above.

The dry thickness of the each hydrophilic overcoat can be at least 100nm and up to and including 800 nm or more particularly at least 300 nmand up to and including 500 nm. In embodiments containing silver halide,the grain ESD to dry thickness ratio in the hydrophilic overcoat can befrom 0.25:1 to and including 1.75:1 or more likely from 0.5:1 to andincluding 1.25:1.

Additional Layers:

In addition to the layers and components described above on one or bothsupporting sides of the transparent substrate, the precursors andelectrically-conductive articles can also include other layers that arenot essential but can provide additional properties or benefits,including but not limited to radiation absorbing filter layers, adhesionlayers, and other layers as are known in the black-and-whitephotographic art. The radiation absorbing filter layers can also beknown as “antihalation” layers that can be located between the essentiallayers and each supporting side of the transparent substrate. Forexample, each supporting side can have a radiation absorbing filterlayer disposed directly on it, and directly underneath thephotosensitive silver halide emulsion layer. Such radiation absorbingfilter layers can include one or more filter dyes that absorb in the UV,red, green, or blue regions of the electromagnetic spectrum, or anycombination thereof, and can be on located between the transparentsubstrate and the photosensitive silver halide emulsion layer on each orboth supporting sides of the transparent substrate.

The duplex electrically-conductive film element precursors used in thepresent invention can comprise on the opposing second supporting side ofthe transparent substrate, a second photosensitive silver halideemulsion layer and optionally, a second hydrophilic overcoat disposedover the second photosensitive silver halide emulsion layer. A radiationabsorbing filter layer can be disposed between the opposing secondsupporting side of the transparent substrate and the secondphotosensitive silver halide emulsion layer, which radiation absorbingfilter layer can be the same as or different from the radiationabsorbing filter layer on the first supporting side of the transparentsubstrate. For example, such radiation absorbing filter layers caninclude one or more UV radiation absorbing compounds.

In many duplex electrically-conductive film element precursors, thesecond photosensitive silver halide emulsion layer and a secondhydrophilic overcoat (if present) have the same composition as the firstphotosensitive silver halide emulsion layer and the first hydrophilicovercoat, respectively.

Preparing Conductive Film Element Precursors

The various layers are formulated using appropriate components andcoating solvents and are applied to one or both supporting sides of asuitable transparent substrate (as described above) using known coatingprocedures including those commonly used in the photographic industry(for example, bead coating, blade coating, curtain coating, spraycoating, and hopper coating). Each layer formulation can be applied toeach supporting side of the transparent substrate in single-passprocedures or in simultaneous multi-layer coating procedures. Knowndrying techniques can be used to dry each of the applied formulations.

Making Electrically-Conductive Articles

The resulting conductive film element precursors can be used immediatelyfor an intended purpose, or they can be stored in roll or sheet form forlater use. For example, the precursors can be rolled up duringmanufacture and stored for use in a roll-to-roll imaging and processingprocess, and subsequently cut into desired sizes and shapes.

To imagewise expose a precursor, a suitable mask element or group ofmask elements are designed with predetermined patterns for bothelectrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns that areeventually formed in the electrically-conductive articles. As notedabove, the photosensitive silver halide emulsion layers in theprecursors are generally designed to accommodate both touch regionshaving desired electrically-conductive silver metal electrode grids, andelectrode connector regions that contain desired electrically-conductivesilver connector wire patterns to provide designed circuitry. Both touchregions and electrode connector regions are formed in the samephotosensitive silver halide emulsion layer on one or both supportingsides of the transparent substrate. The transparent regions outside ofthe electrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns generally containno silver metal particles.

Thus, one or both sides of a precursor are designed to be exposed tosuitable radiation to provide, in each photosensitive silver halideemulsion layer: (a) a latent electrically-conductive silver metalelectrode grid, and (b) a latent electrically-conductive silverconnector wire pattern that is different from the latentelectrically-conductive silver metal electrode grid. Each side of theprecursor can be imagewise exposed at the same time or they can beimagewise exposed at different times using different mask elements sothe opposing latent images in all regions are different in design, size,surface area covered by the silver metal particles, or sheetresistivity. Opposing photosensitive silver halide emulsion layers canalso be designed to have different wavelength sensitivity so thatdifferent imaging (exposing) radiation wavelengths can be used forexposure of opposing supporting sides.

Thus, photosensitive silver halides in photosensitive silver halideemulsion layers can be imagewise exposed to appropriate actinicradiation (UV to visible radiation) from a suitable source that is wellknown in the art such as a xenon lamp, mercury lamp, or other source ofradiation of from 200 nm and up to and including 700 nm.

The exposed precursors can be processed using various aqueous-basedprocessing solutions including at least solution physical developmentand silver halide fixing, to provide in each exposed photosensitivesilver halide emulsion layer: (a) an electrically-conductive silvermetal electrode grid from the latent electrically-conductive silvermetal electrode grid, (b) an electrically-conductive silver connectorwire pattern from the latent electrically-conductive silver connectorwire pattern, and (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern.

The resulting electrically-conductive silver metal electrode grid isformed in the touch region generally has an integrated transmittance ofat least 75% (for example, the electrically-conductive silver metalelectrode grid covers 25% or less of the total touch region surfacearea). Moreover, the resulting electrically-conductive silver connectorwire pattern formed in the electrode connector regions has an integratedtransmittance of 68% or less (or 50% or less). Thus, theelectrically-conductive silver connector wire pattern generally coversmore than 42% of the total electrode connector region. Integratedtransmittance is determined as described above. These amounts can be thesame or different on opposing supporting sides of the transparentsubstrate.

Prebath solutions can also be used to treat the exposed silver saltsprior to development. Such solutions can include one or more developmentinhibitors as described above for the developing solutions, and in thesame or different amounts. Effective inhibitors include but are notlimited to, benzotriazoles, heterocyclic thiones, andmercaptotetrazoles. The prebath temperature can be in a range asdescribed for development. Prebath time depends upon the concentrationand particular inhibitor, but it can range from at least 10 seconds andup to and including 4 minutes.

Processing the exposed silver halide in the latent images is generallyaccomplished firstly with one or more development steps during whichsilver ions in the silver halide latent images are reduced to silvermetal (or silver particles). Such development steps are generallycarried out using known aqueous developing solutions that are commonlyused in silver metal image-forming black-and-white photography andtypically include at least one solution physical development solution.

Numerous silver metal image-forming black-and-white developing solutions(identified also as “developers”) are known that can develop the exposed(latent image containing) silver halides described above to form silvermetal particles. One commercial silver metal image-formingblack-and-white silver halide developer that is useful is Accumax®silver halide developer. Silver metal image-forming black-and-whitedeveloping solutions are generally aqueous solutions including one ormore silver halide developing agents, of the same or different type,including but not limited to those described in Research Disclosure Item17643 (December, 1978) Item 18716 (November, 1979), and Item 308119(December, 1989) such as polyhydroxybenzenes (such as dihydroxybenzene,or in its form as hydroquinone, cathecol, pyrogallol,methylhydroquinone, and chlorohydroquinone), aminophenols such asp-methylaminophenol, p-aminophenol, and p-hydroxyphenylglycine,p-phenylenediamines, ascorbic acid and its derivatives, reductones,erythrobic acid and its derivatives, 3-pyrazolidones such as1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-3-pyrazolidone, and1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, pyrazolone,pyrimidine, dithionite, and hydroxylamines. These developing agents canbe used individually or in combinations thereof. One or more developingagents can be present in suitable amounts for example of at least 0.01mol/l and up to and including 1 mol/l.

The black-and-white developing solutions can also include auxiliarysilver developing agents that exhibit super-additive properties with adeveloping agent. Such auxiliary developing agents can include but arenot limited to, p-aminophenols and substituted or unsubstitutedphenidones, in suitable amounts such as at least 0.001 mo/l and up toand including 0.1 mol/l.

The concentration of the one or more auxiliary silver developing agentscan be less than the concentration of the one or more developing agentsas described above.

Useful black-and-white developing solutions can also include one or moresilver complexing agents (or silver ligands) including but not limitedto, sulfite, thiocyanate, thiosulfate, thiourea, thiosemicarbazide,tertiary phosphines, thioethers, amines, thiols, aminocarboxylates,triazolium thiolates, pyridines (including bipyridine), imidazoles, andaminophosphonates, in known amounts. For example, one or more alkalimetal sulfites can be present in an amount of at least 0.1 mol/l and upto and including 1 mol/l.

The black-and-white developing solutions can also comprise one or morealkyl- or aryl-substituted or unsubstituted mercaptotetrazoles insuitable amounts for various purposes such as at least 0.25 mmol/l andup to and including 2.5 mmol/l. Useful mercaptotetrazoles include butare not limited to, alkyl-, aryl-, and heterocyclyl-substitutedmercaptotetrazoles. Examples of such compounds include but are notlimited to, 1-phenyl-5-mercaptotetrazole (PMT),1-ethyl-5-mercaptotetrazole, 1-t-butyl-5-mercaptotetrazole, and1-pyridinyl-5-mercaptotetrazoles.

Moreover, the black-and-white developing solution can also include oneor more development inhibitors in suitable amounts. Useful developmentinhibitors include but are not limited to, substituted and unsubstitutedbenzotriazole compounds such as 5-methylbenzotriazole, imidazoles,benzimidazole thiones, benzotbiazole thiones, benzoxazole thiones, andthiazoline thiones, all in the same or different amounts as describedabove for the mercaptotetrazoles.

Other addenda that can be present in the black-and-white developingsolutions in known amounts include but are not limited to, metalchelating agents, preservatives (such as sulfites), antioxidants, smallamounts of water-miscible organic solvents (such as benzyl alcohol anddiethylene glycol), nucleators, as well as acids, bases (such as alkalihydroxides), and buffers (such as carbonate, borax, phosphates, andother basic salts) to establish a pH of at least 8 and generally of a pHof at least 9.5, or at least 11 and up to and including 14.

The silver halide developing solution can be supplied at workingstrength or in concentrated form that is diluted prior to or during useup to 5 times with water.

Multiple development steps can be used if desired. For example, a firstdeveloping solution can provide initial development to form silver metalnuclei and then a second developing solution can be used to provide“solution physical development” that improves conductivity of theresulting silver metal images.

A solution physical development step can be carried out using a solutionhaving a pH of at least 8 and up to and including 13. This silver halidesolution physical developing solution can comprise one or more primarydeveloping agents chosen from one or more of hydroquinone or itsderivatives or one or more ascorbic acid or derivatives thereof. Theprimary developing agents in the silver halide solution physicaldeveloping solution can be the same or different as the primarydeveloping agents in the silver halide developing solution describedabove.

The one or more primary developing agents in the silver halide solutionphysical developing solution can be present in a total amount of atleast 0.01 mol/l and up to and including 1 mol/l.

In addition, the silver halide solution physical developing solutioncomprises one or more silver halide dissolution catalysts as essentialcomponents in an amount of at least 0.001 mol/l and up to and including0.1 mol/l, or typically of at least 0.005 mol/l and up to and including0.05 mol/l.

Useful silver halide dissolution catalysts include but are not limitedto, alkali metal thiocyanate salts such as sodium thiocyanate andpotassium thiocyanate, thioethers such as 3,6-dithia-1,8-octanediol, andheterocyclic thiones such astetrahydro-4,6-dimethyl-1,3,5-triazine-2(1H)-thione, andtetrahydro-3-hydroxyethyl-1,3,5-triazine-2(1H)-thione. These compoundscan readily complex with silver.

In some embodiments, the silver halide solution physical developingsolution contains substantially no catalytic developing agents such asthose compounds described above for the silver halide developingsolution. The term “substantially no” means that less than 0.001 mol/lor even less than 0.0001 mol/l of such compounds are purposelyincorporated into or created in the solution.

The silver halide solution physical developing solution can furthercomprise one or more alkali metal sulfites include sodium sulfite,potassium sulfite, and mixtures thereof. The alkali metal sulfites canbe present in the silver halide solution physical developing solution ina total amount of at least 0.2 mol/l and up to and including 3 mol/lwhen potassium sulfite or sodium sulfite is used or particularly whenonly potassium sulfite is used.

The silver halide solution physical developing solution can furtherinclude one or more polyaminopolycarboxylic acid salts that are capableof complexing with silver ion, including but not limited to,diethylenetriamine pentaacetic acid, pentasodium salt and other similarcompounds known in the art. Such compounds can be useful particularlywhen a sulfite is not present. Such compounds can be present in anamount of at least 0.001 mol/l and up to and including 0.03 mol/l.

The silver halide solution physical developing solution can also includeone or more metal ion complexing agents that can complex with silver,calcium, iron, magnesium, or other metal ions that can be present.Silver or calcium metal ion complexing agents can be particularly usefulin a total amount of at least 0.001 mol/l.

Particularly useful silver halide solution physical developing solutionsinclude but are not limited to, hydroquinone or a derivative thereof andsodium thiocyanate or potassium thiocyanate, and optionally a sulfiteand calcium or silver metal ion complexing agent.

The silver halide physical solution developing solution can be providedat working strength or in a concentrated form that is suitably dilutedprior to or during processing using known processing equipment andprocedures. For example, the silver halide physical developing solutioncan be concentrated at least 4 times compared to a desired workingstrength concentration.

Useful development temperatures can range from at least 15° C. and up toand including 60° C. Useful development times can range from at least 10seconds and up to and including 10 minutes but more likely up to andincluding 1 minute. The same time or temperature can be used forindividual development steps and can be adapted to develop at least 90mol % of the exposed silver halide in all latent silver halide images.If a prebath solution is not used, the development time can be extendedappropriately. Any exposed silver halide(s) in a hydrophilic overcoat isalso developed during the development step(s). Washing or rinsing can becarried out with water after or between any development steps.

After development of the exposed silver halide to silver metal, theundeveloped silver halide in all photosensitive silver halide emulsionlayers is generally removed by treating the developed silver-containingarticle with a silver halide fixing solution. Silver halide fixingsolutions are well known in the black-and-white photographic art andcontain one or more compounds that complex the silver ion for removalfrom the layers. Thiosulfate salts are commonly used in silver halidefixing solutions. The silver halide fixing solution can optionallycontain a hardening agent such as alum or chrome-alum. The developedfilm can be processed in a silver halide fixing solution immediatelyafter development, or there can be an intervening stop bath or waterwash or rinse, or both stop bath and water rinse. Fixing can be carriedout at any suitable temperature and time such as at least 20° C. for atleast 30 seconds.

Fixing then leaves the silver metal particles in the conductive silvermetal electrode grid and electrically-conductive silver connector wirepattern in each formerly photosensitive silver halide emulsion layer.Fixing also removes any non-developed silver halide in any hydrophilicovercoat.

After fixing, the resulting intermediate article can be washed or rinsedin water that can optionally include surfactants or other materials toreduce water spot formation upon drying.

After fixing, the intermediate article can be further treated to furtherenhance the conductivity of the silver metal (or nuclei) on eachsupporting side of the transparent substrate. A variety of ways havebeen proposed to carry out this “conductivity enhancement” process. Forexample, U.S. Pat. No. 7,985,527 (Tokunaga) and U.S. Pat. No. 8,012,676(Yoshiki et al.) describe conductivity enhancement treatments using hotwater baths, water vapor, reducing agents, or halides.

It is also possible to enhance conductivity of the silver metalparticles by repeated contact with a conductivity enhancing agent,washing, drying, and repeating this cycle of treating, washing, anddrying one or more times. Useful conductivity enhancing agents includebut are not limited to, sulfites, borane compounds, hydroquinones,p-phenylenediamines, and phosphites. The treatment can be carried out ata temperature of at least 30° C. and up to and including 90° C. for atleast 0.25 minute and up to and including 30 minutes.

It can be useful in some embodiments to treat theelectrically-conductive article with a hardening bath after fixing andbefore drying to improve the physical durability of the resultingconductive article. Such hardening baths can include one or more knownhardening agents in appropriate amounts that would be readily apparentto one skilled in the art. It can be desired to control the swelling ofthe conductive film element precursor at one or more stages ofprocessing, so that swelling is limited to a desired amount of theoriginal precursor dry thickness.

Additional treatments such as a stabilizing treatment can also becarried out before a final drying if desired, at any suitable time andtemperature.

Drying at any stage can be accomplished in ambient conditions or byheating, for example, in a convection oven at a temperature above 50° C.but below the glass transition temperature of the transparent substrate.

While imagewise exposing and processing of each side of the precursorcan be carried out at different times or sequences, in many embodiments,imagewise exposing and processing of the photosensitive silver halideemulsion layer on the opposing second supporting side of the transparentsubstrate is carried out simultaneously with imagewise exposing andprocessing of the photosensitive silver halide emulsion layer on thefirst supporting side.

The result of the processing steps is an electrically-conductive articleas described herein.

Electrically-Conductive Silver Metal Grids:

The electrically-conductive silver metal electrode grid on the firstsupporting side and the optional electrically-conductive silver metalgrid on the opposing second supporting side can be the same or differentin composition, pattern arrangement, conductive line thickness, or shapeof the grid lines (for example, a pattern of polygons including but notlimited to, a pattern of rectangles, triangles, hexagons, rhombohedrals,octagons, or squares), circles or other curved lines, or randomstructures, all corresponding to the predetermined pattern in the maskelement used during imagewise exposure. For example, in one embodiment,the electrically-conductive silver metal electrode grid on the firstsupporting side can be arranged in a square pattern, and theelectrically-conductive silver metal electrode grid on the opposingsupporting second side can be arranged in a diamond pattern. In eachinstance, the silver grid lines in the electrically-conductive silvermetal grids form a net-like structure. In other embodiments, the variouspatterns on opposing supporting sides can be arranged in an alternativearrangement so that the electrically-conductive silver metal electrodegrid on one supporting side only partially covers theelectrically-conductive silver metal electrode grid on the opposingsupporting side, somewhat as is shown in FIG. 14 of U.S. PatentApplication Publication 2011/0289771 (noted above).

The electrically-conductive silver wires in the electrically-conductivesilver metal electrode grid can have any desired length that is usuallyat least 1 cm and up to and including 10 meters, and they can have anaverage dry thickness (line width, one outer edge to the other outeredge) and dry height that are the same or different, and are generallyless than 50 μm, but more likely at least 1 μm and up to and including20 μm, or particularly at least 5 μm and less than 15 μm or even 10 μmor less.

Electrically-Conductive Silver Wire Patterns:

Each electrically-conductive silver connector wire pattern comprises atleast one and more likely at least two adjacent (for example, at leastfirst and second) silver main wires, and there can be up to 1000 or evenmore of these silver main wires in each electrically-conductive silverconnector wire pattern. The number of silver main wires can be differenton opposing supporting sides of the transparent substrate. Each silvermain wire comprises two or more (and up to 10 or even more) silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one (generally at least two adjacent) silver mainwires. Thus, the two or more silver micro-wires and the silver end wirein each silver main wire forming a bundled pattern. Many bundledpatterns comprise a plurality of silver main wires, each of whichcomprises a plurality of silver micro-wires and all of the silvermicro-wires are electrically connected at both ends to suitable silverend wires. As described below, such bundled patterns can also includeone or more silver cross-wires.

In some embodiments, each silver main wire can comprise from two toeight silver micro-wires that with the suitable silver end wires form abundled pattern. Thus, each bundled pattern in such embodimentscomprises a conductive silver end wire at each end of the at least twoadjacent silver main wires (and thus at the end of each pair of adjacentsilver main wires in the bundled pattern) that electrically connectswith the two to eight silver micro-wires in each bundled pattern.

The average distance between any two adjacent silver main wires isgreater than the average distance between any two adjacent silvermicro-wires in each bundled pattern. For example, the average distancebetween any two adjacent silver main wires can be greater than theaverage distance between any two adjacent silver micro-wires in eachbundled pattern by at least 30%, or more typically at least 100%. Forexample, the average distance between two adjacent silver main wires canbe at least 5 μm, or at least 10 urn, or even at least 20 μm. Such“average distances” are measured from the outer edge of a given silvermicro-wire to the nearest outer edge of an adjacent silver micro-wire,or from the outer edge of the outermost silver micro-wire in a givensilver main wire to the outer edge of the closest outermost silvermicro-wire in an adjacent silver main wire.

Within each silver main wire, the average total length of each silvermicro-wire can be at least 1 mm or typically at least 5 mm and up to andincluding 1000 mm.

The average distance between any two adjacent silver micro-wires in eachbundled pattern (of each and any silver main wire) can be at least 2 μmand up to and including 10 μm (wherein “average distance” is definedabove). In particular, the average distance between any two adjacentsilver micro-wires in each bundled pattern (or each and any silver mainwire) can be at least 5 μm and up to and including 8 μm.

The ratio of the average width (outer edge to opposing outer edge) ofeach silver micro-wire to the average distance between two adjacentsilver micro-wires in each bundled pattern (or each and any silver mainwire) can be at least 0.5:1 but less than 2:1, or typically at least 1:1and up to and including 2:1.

It is also desirable that for each silver micro-wire, the ratio ofmaximum height to minimum height can be at least 1.05:1, or typically atleast 1.1:1.

In some embodiments of at least one of the silver micro-wires (and inmost embodiments, each silver micro-wire), the maximum height of thesilver micro-wire can be equivalent (varying by less than 10%) to thecenter height of the silver micro-wire wherein the “center” isdetermined to be essentially equidistant between the two outer edges ofthe silver micro-wire. “Essentially equidistant” means that thedistances between the two outer edges vary by no more than 10%.

In other embodiments of at least one of the silver micro-wires (and inmost embodiments, each silver micro-wire), the maximum height can becloser to a micro-wire outer edge than to micro-wire center height (atleast 51% closer to the outer edge than to the center). For example, themaximum height can actually be located at one or both outer edges ofsome silver micro-wires.

It is also possible that for each silver micro-wire, the ratio ofmaximum height to average height can be at least 1.01:1, or moretypically at least 1.01:1 to and including 1,05:1.

The average width of each silver micro-wire (from one outer edge to theother outer edge) in each bundled pattern can be at least 2 μm and up toand including 20 μm, or typically up to and including 15 μm or typicallyfrom 2 μm and up to and including 12 μm.

Moreover, each bundled pattern can comprise at least one silvercross-wire between adjacent silver micro-wires that is not at the end ofthe adjacent silver micro-wires. Typically, adjacent silver micro-wirescomprise multiple silver cross-wires that are not at the end of adjacentsilver micro-wires. A skilled worker can design each bundled pattern tohave as many silver cross-wires as can be desired for a givenelectrically-conductive silver connector wire pattern.

The silver cross-wires can be arranged in any suitable frequency ordirectional arrangement and such arrangement can be the same ordifferent for each set of adjacent silver micro-wires.

For example, each bundled pattern can comprise multiple (two or more)silver cross-wires between adjacent silver micro-wires, wherein themultiple silver cross-wires are arranged at a distance from each otherof at least 100 μm.

Moreover, each bundled pattern can comprise multiple (two or more)silver cross-wires in a set of adjacent silver micro-wires that areoffset from multiple silver cross-wires in an another set of adjacentsilver micro-wires (for example alternating along the adjacent sets ofadjacent silver micro-wires). All of the silver cross-wires cantherefore be arranged in the same or different manner among all of theadjacent sets of adjacent silver micro-wires.

In some embodiments, each of the multiple silver cross-wires issubstantially perpendicular (intersection at an angle of substantially90°) to the adjacent silver micro-wires. In other embodiments, each ofthe multiple silver cross-wires intersects the adjacent silvermicro-wires at an angle that is greater than or less than 90°. The twoor more silver micro-wires can be substantially parallel (for example,the adjacent silver micro-wires are substantially parallel).

The present invention can also be exemplified in reference to FIGS. 1-11that are now explained.

In FIG. 1, electrically-conductive article 5 has transparent substrate40 on which electrically-conductive silver connector wire pattern 8 isdisposed, which electrically-conductive silver connector wire pattern 8comprises multiple silver main wires 10. Each silver main wire 10comprises multiple adjacent silver micro-wires 20 (four shown in FIG. 1for each silver main wire 10). Silver end wire 22 is shown at the end ofeach silver main wire 10. Outside of electrically-conductive silver wireconnector pattern 8 is transparent region 50 (referenced in some but notall places). Transparent regions (not shown with additional referencenumbers) are also present between (or outside) adjacent silver mainwires 10 and between (or outside) adjacent silver micro-wires 20 in eachsilver main wire 10. All transparent regions contain no significantsilver halide or silver metal. In electrically-conductive article 5,adjacent silver main wires (at least one identified as 10) are separatedby distance S1 and the distance between adjacent silver micro-wires (oneidentified as 20) is shown by S2. As described above, the average S1 isgreater than the average S2 in each bundled pattern (silver main wire10). Representative average silver micro-wire 20 width is shown as W andaverage silver micro-wire length is shown as L. Each silver micro-wire20 can have essentially the same or different L and W dimensions. Inmost embodiments, such dimensions are the same for each silvermicro-wire in a given silver main wire.

FIG. 2 shows a schematic cross-section of electrically-conductivearticle 5 comprising transparent substrate 40 having first supportingside 42 and opposing second supporting side 44. A representative silvermicro-wire 20 is shown on both first supporting side 42 and opposingsecond supporting side 44.

In the cross-section view shown in FIG. 3A, a portion of photosensitivesilver halide emulsion layer 15 is disposed on a supporting side (eitherfirst supporting side or opposing second supporting side) of transparentsubstrate 40 having first supporting side 42 and opposing secondsupporting side 44. This portion of photosensitive silver halideemulsion layer 15 contains multiple non-exposed and non-developed silverhalide grains 60 surrounded by hydrophilic binder 64.

FIG. 3B shows a similar view as FIG. 3A but silver micro-wire 20 isdisposed on transparent substrate 40 having first supporting side 42 andopposing second supporting side 44, which silver micro-wire 20 containsmultiple silver metal particles 62 that can be derived from exposure andsilver halide development of the multiple silver halide grains 60surrounded by hydrophilic binder 64, shown in the portion ofphotosensitive silver halide emulsion layer 15 illustrated in FIG. 3A.

FIG. 4 is similar to FIG. 1 and shows electrically-conductive article 5comprising transparent substrate 40 on which electrically-conductivesilver connector wire pattern 8 is disposed. Electrically-conductivesilver connector wire pattern 8 comprises multiple silver main wires 10.Three silver main wires 10 are shown but electrically-conductive silverconnector wire pattern 8 can have as few as two silver main wires.Moreover, while only four silver micro-wires 20 are shown for eachsilver main wire 10, the number of silver micro-wires in each main wirecan be as few as two and up to and including ten. Silver end wires 22are shown at the end of each set of adjacent silver micro-wires 20 andvarious silver cross-wires 24 (only some are referenced) are shown atthe same interval along silver micro-wires 20. Outside ofelectrically-conductive silver connector wire pattern 8 is transparentregion 50 (referenced in only some places), but transparent regions (notreferenced) also exist between adjacent silver micro-wires and betweenadjacent silver main wires.

FIG. 5 is similar to FIG. 4 but silver cross-wires 24 are arranged atdifferent intervals along silver micro-wires 20 and are offset betweenpairs of adjacent silver micro-wires 20. Thus, each bundled pattern orsilver main wire 10 comprises multiple silver cross-wires 24 in a set ofadjacent silver micro-wires 20, which are offset from multiple silvercross-wires 24 in an adjacent set of adjacent silver micro-wires 20.

FIG. 6 shows representative portions of some embodiments of the methodof this invention in which a conductive film element precursor(“precursor”) is provided in feature 100, imagewise exposed to suitableradiation in feature 105, and the resulting latent silver is processed[including development using suitable silver metal image-formingblack-and-white developing solution(s)] in the precursor in feature 110.

FIG. 7 shows representative portions of other embodiments in which aprovided duplex conductive film element precursor (“precursor”) isimagewise exposed in feature 105 in two individual features of imagewiseexposure of a first side of the duplex conductive film element precursorin feature 107 and sequential imagewise exposure of the second (oropposing) side of the duplex conductive film element precursor infeature 109, followed by processing (including development) of theresulting latent silver in both imagewise exposed sides of the precursorin feature 110.

FIG. 8 shows representative portions of yet another variation in whichimagewise exposure feature 105 is carried out simultaneously for bothfirst and second sides of a duplex conductive film element precursor(“precursor”) as shown in features 107 and 109, and then followed byprocessing (including development) of latent silver on both sides of theimagewise exposed precursor in feature 110.

Still other representative portions of the method of this invention areshown in FIG. 9 in which imagewise exposure of a first side of a duplexconductive film element precursor (“precursor”) is provided in 107,which imagewise exposed first side is then processed (for example,development) to provide silver metal particles from latent silver infeature 112. The second (or opposing) side of the duplex conductive filmelement precursor is then imagewise exposed in 109 following byappropriate processing (including development) of latent silver tosilver metal particles in the precursor in feature 114.

FIG. 10 is a schematic cross-sectional view of a typical silvermicro-wire 20 that has a rounded upper and outer surface, and isdisposed on transparent substrate 40 having first supporting side 42 andopposing second supporting side 44. Silver micro-wire 20 is thereforecomposed of multiple silver metal nuclei (particles) 62 surrounded byhydrophilic binder 64, which have been derived for example fromappropriate silver halide grains using the chemical compositions,appropriate exposure, and processing chemistry described above. As shownin FIG. 10, silver micro-wire 20 has average width W, silver micro-wiremaximum height D1, and silver micro-wire minimum height D2, whereinsilver micro-wire maximum height D1 is greater than silver micro-wireminimum height D2 for example by a ratio of at least 1.05:1. While FIG.10 illustrates a silver micro-wire that has uniform dimensions andcontours, it would be understood by a skilled artisan that the drawnillustration is representative only and that actual silver micro-wiresproduced in the practice of this invention can have more irregular outersurfaces and shapes.

FIG. 11 is another schematic cross-sectional view showing a differentshape for silver micro-wire 20 containing multiple silver metalparticles 62 surrounded in hydrophilic binder 64, which silvermicro-wire 20 is disposed on transparent substrate 40 having firstsupporting side 42 and opposing second supporting side 44. Silvermicro-wire minimum height D2 is at or near the center of silvermicro-wire 20, and silver micro-wire minimum height D2 is less thansilver micro-wire maximum height D1 that is near or at either or bothouter edges of silver micro-wire 20. As one skilled in the art wouldunderstand, such illustration of silver micro-wire 20 is representativeonly and actual silver micro-wires produced in the practice of thisinvention can exhibit maximum and minimum heights that vary considerablyfrom that shown and can thus have more irregular outer surfaces.

The present invention provides at least the following embodiments andcombinations thereof, but other combinations of features are consideredto be within the present invention as a skilled artisan would appreciatefrom the teaching of this disclosure:

1. A method for providing an electrically-conductive article of any ofembodiments described herein, the method comprising:

imagewise exposing a conductive film element precursor that comprises atransparent substrate comprising a first supporting side and an opposingsecond supporting side and a photosensitive silver halide emulsion layeron at least the first supporting side, to radiation to provide, in thephotosensitive silver halide emulsion layer on at least the firstsupporting side: (a) a latent electrically-conductive silver metalelectrode grid, (b) a latent electrically-conductive silver connectorwire pattern different from the latent electrically-conductive silvermetal electrode grid, and optionally, (c) transparent regions outside ofboth the latent electrically-conductive silver metal electrode grid andthe latent electrically-conductive silver connector wire pattern; and

processing the latent electrically-conductive silver metal electrodegrid and latent electrically-conductive silver connector wire patternusing at least solution physical development and silver halide fixing,to provide: (a) an electrically-conductive silver metal electrode gridfrom the latent electrically-conductive silver metal electrode grid, (b)an electrically-conductive silver connector wire pattern from the latentelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the electrically-conductivesilver metal electrode grid and the electrically-conductive silverconnector wire pattern,

-   -   wherein    -   (i) the electrically-conductive silver connector wire pattern        comprises at least one silver main wire that comprises two or        more silver micro-wires that are electrically connected to a        silver end wire at an end of the at least one silver main wire,        the two or more silver micro-wires and the silver end wire in        the at least one silver main wire forming a bundled pattern;    -   (ii) the average length of each silver micro-wire is at least 1        mm;    -   (iii) the ratio of the average width of each silver micro-wire        to the average distance between two adjacent silver micro-wires        in each bundled pattern is at least 0.5:1 but less than 2:1;    -   (iv) the electrically-conductive silver connector wire pattern        has an integrated transmittance of less than 68%; and    -   (v) for each silver micro-wire, the ratio of maximum height to        minimum height is at least 1.05:1.

2. The method of embodiment 1, wherein the electrically-conductivesilver connector wire pattern comprises at least two adjacent silvermain wires, and the average distance between the at least two adjacentsilver main wires is greater than the average distance between any twoadjacent silver micro-wires in each bundled pattern.

3. The method of embodiment 2, wherein the average distance between anytwo adjacent silver micro-wires in each bundled pattern is at least 2 μmand up to and including 10 μm.

4. The method of any of embodiments 1 to 3, wherein the conductive filmelement precursor further comprises a photosensitive silver halideemulsion layer disposed on the opposing second supporting side of thetransparent substrate, and

-   -   the method further comprising:

imagewise exposing the photosensitive silver halide emulsion layer onthe opposing second supporting side of the transparent substrate toprovide (a) an opposing latent electrically-conductive silver metalelectrode grid, (b) an opposing latent electrically-conductive silverconnector wire pattern different from the opposing latentelectrically-conductive silver metal electrode grid, and optionally, (c)transparent regions outside of both the opposing latentelectrically-conductive silver metal electrode grid and the opposinglatent electrically-conductive silver connector wire pattern; and

processing the opposing latent electrically-conductive silver metalelectrode grid and the opposing latent electrically-conductive silverconnector wire pattern using at least solution physical development andsilver halide fixing, to provide: (a) an opposingelectrically-conductive silver metal electrode grid from the opposinglatent electrically-conductive silver metal electrode grid, (b) anopposing electrically-conductive silver connector wire pattern from theopposing latent electrically-conductive silver connector wire pattern,and optionally, (c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern on the opposingsecond supporting side of the transparent substrate,

-   -   wherein, on the opposing second supporting side of the        transparent substrate:    -   the opposing electrically-conductive silver connector wire        pattern comprises at least one silver main wire that comprises        two or more silver micro-wires that are electrically connected        to a silver end wire at an end of the at least one silver main        wire, the two or more silver micro-wires and the silver end wire        in the at least one silver main wire forming a bundled pattern;    -   (ii) the average length of each silver micro-wire is at least 1        mm;    -   (iii) the ratio of the average width of each silver micro-wire        to the average distance between two adjacent silver micro-wires        in each bundled pattern is at least 0.5:1 but less than 2:1;    -   (iv) the opposing electrically-conductive silver connector wire        pattern has an integrated transmittance of less than 68%; and    -   (v) for each silver micro-wire, the ratio of maximum height to        minimum height is at least 1.05:1.

5. The method of embodiment 4, wherein the opposingelectrically-conductive silver connector wire pattern comprises at leasttwo adjacent silver main wires, and the average distance between the atleast two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.

6. The method of embodiment 4 or 5, wherein the average distance betweenany two adjacent silver micro-wires in each bundled pattern on theopposing second supporting side of the transparent substrate is at least2 μm and up to and including 10 μm.

7. The method of any of embodiments 4 to 6, wherein imagewise exposingand processing of the photosensitive silver halide emulsion layer on theopposing second supporting side of the transparent substrate are carriedout simultaneously with imagewise exposing and processing of thephotosensitive silver halide emulsion layer on the first supporting sideof the transparent substrate.

8. The method of any of embodiments 1 to 7, wherein for each silvermicro-wire, the ratio of maximum height to minimum height is at least1.1:1.

9. The method of any of embodiments 1 to 8, wherein at least one silvermicro-wire has a maximum height that is the same as its center height.

10. The method of any of embodiments 1 to 8, wherein at least one silvermicro-wire has a maximum height that is closer to its outer edge than toits center height.

11. The method of any of embodiments 1 to 10, wherein each silvermicro-wire has a ratio of maximum height to average height of at least1.05:1.

12. The method of any of embodiments 1 to 11, wherein the average widthof each silver micro-wire is at least 5 μm and up to and including 20μm.

13. The method of any of embodiments 1 to 12, wherein each bundledpattern comprises at least one silver cross-wire between adjacent silvermicro-wires that is not at the end of the adjacent silver micro-wires.

14. The method of any of embodiments 1 to 13, wherein each bundledpattern comprises multiple silver cross-wires between adjacent silvermicro-wires, wherein the multiple silver cross-wires are arranged at adistance from each other of at least 100 μm.

15. The method of any of embodiments 1 to 14, wherein each bundledpattern comprises multiple silver cross-wires in a set of adjacentsilver micro-wires that are offset from multiple silver cross-wires inan adjacent set of adjacent silver micro-wires.

16. The method of embodiment 14 or 15, wherein each of the multiplesilver cross-wires is substantially perpendicular to the adjacent silvermicro-wires.

17. The method of any of embodiments 1 to 16, wherein the averagedistance between any two adjacent silver main wires is greater than theaverage distance between any two adjacent silver micro-wires in eachbundled pattern by at least 30%.

18. The method of any of embodiments 1 to 17, wherein the ratio of theaverage width of each silver micro-wire to the average distance betweentwo adjacent silver micro-wires in each bundled pattern is at least 1:1and up to and including 2:1.

19. The method of any of embodiments 1 to 18, wherein theelectrically-conductive silver connector wire pattern has an integratedtransmittance of less than 50% and the electrically-conductive silvermetal electrode grid has an integrated transmittance of at least 90%.

20. The method of any of embodiments 4 to 19, wherein the opposingelectrically-conductive silver connector wire pattern has an integratedtransmittance of less than 50% and the opposing electrically-conductivesilver metal electrode grid has an integrated transmittance of at least90%.

The present invention can be carried out using a photosensitive silverhalide emulsion layer (from the silver halide emulsion described below)that can be disposed on one or both supporting sides of a transparentpoly(ethylene terephthalate) film substrate in any suitable coatingmanner to form a conductive film element precursor used in the presentinvention.

The conductive film element precursors can also be prepared using a 100μm poly(ethylene terephthalate) substrate on which a non-colorphotosensitive silver halide emulsion can be hardened using BVSM[1,1′-(methylene(sulfonyl))bis-ethane] and disposed at 0.5 weight % oftotal gelatin. However, underneath the silver halide emulsion layer, afilter layer can be directly disposed on the transparent substrate forUV absorption, containing 1500 mg/m² of gelatin and 300 mg/m² ofTINUVIN® 328 UV absorbing dye (for example from BASF).

The non-color photosensitive silver halide emulsion layer can beprovided with a silver (Ag) to gelatin weight ratio of 2.33:1 (or at avolume ratio of about 0.233:1). If desired, an outermost hydrophilicovercoat layer can be provided over the non-color photosensitive silverhalide emulsion layer, containing 488 mg/m² of gelatin, 6 mg/m² of 0.6μm insoluble polymeric matte particles, and conventional coatingsurfactants.

This conductive film element precursor can be imagewise exposed on oneor both sides using a suitable exposing device through the same ordifferent mask elements that have predetermined reverse images for theeventual desired electrically-conductive silver wire electrode grid andan electrically-conductive silver connector wire pattern on one or bothsupporting sides of the precursor. Upon exposure of one or bothphotosensitive silver halide emulsion layers, (a) a latentelectrically-conductive silver metal electrode grid, (b) a latentelectrically-conductive silver connector wire pattern different from thelatent electrically-conductive silver metal electrode grid, andoptionally, (c) transparent regions outside of both the latentelectrically-conductive silver metal electrode grid and the latentelectrically conductive silver connector wire pattern can be formed.

Following imagewise exposure, each latent electrically-conductive silvermetal electrode grid and latent electrically-conductive silver connectorwire pattern can be processed using at least solution physicaldevelopment and silver halide fixing, to provide: (a) anelectrically-conductive silver metal electrode grid from the latentconductive silver metal electrode grid, (b) an electrically-conductivesilver connector wire pattern from the latent electrically-conductivesilver connector wire pattern, and (c) transparent regions outside ofboth the electrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern, in a resultingelectrically-conductive article.

Such processing can be carried out using the processing solutionsdescribed below, so that the resulting electrically-conductive articlewould have one or more of the properties (i) through (v) describedabove.

TABLE I Processing Sequence Processing Processing Temperature Time,Processing Step/Solution (° C.) (minutes) Developing/developer 1 40 0.5Washing/rinsing with water 40 1.0 Developing/developer 2 40 3.0Fixing/fixing solution 40 1.77 Washing/rinsing with water 40 1.0Conductivity 60 2.0 Enhancement/Conductivity Enhancement SolutionWashing/rinsing with water 40 1.0 Drying 60 15.0 Conductivity 60 2.0Enhancement/Conductivity Enhancement Solution Washing/rinsing with water40 1.0 Drying 60 15.0 Conductivity 60 2.0 Enhancement/ConductivityEnhancement Solution Washing/rinsing with water 40 1.0 Drying 60 15.0Stabilizing/Stabilizer Solution 40 1.0 Washing/rinsing with water 40 1.0

The aqueous processing solutions that can be used in the notedprocessing steps are described below in TABLES II through VI, all ofwhich can be prepared in de-mineralized water. Drying can be carried outusing a convection oven.

TABLE II Developer 1 Component Amount (g/liter) Potassium Hydroxide(45.5 wt. %) 10.83 Sodium Bromide 5.00 4,4-Dimethyl-1-phenyl-3- 0.33pyrazolidinone 1-Phenyl-5-mercaptotetrazole 0.13 5-methylbenzotriazole*0.17 Sodium hydroxide (50 wt. %) 1.82 Phosphonic acid, 0.29[nitrilotris(methylene)]tris-, pentasodium saltN,N′-1,2-ethanediylbis(N- 1.77 (carboxymethyl)glycine, Sodium carbonatemonohydrate 8.33 Potassium Sulfite (45 wt. %) 83.33 Hydroquinone 12.505,5′[Dithiobis(4,1- 0.12 phenyleneimino)]bis(5-oxo- pentanoic acid

TABLE III Developer 2 Component Amount (g/liter) Sodium Sulfite 92.54Hydroquinone 4.63 N,N-bis(2-(bis(carboxymethyl)- 0.950 amino)ethyl)-glycine, pentasodium salt Sodium tetraborate pentahydrate 2.830 Sodiumthiocyanate 0.42

TABLE IV Fixing Solution Component Amount (g/liter) Acetic Acid 24.43Sodium hydroxide (50 wt. %) 10.25 Ammonium thiosulfite 246.50 Sodiummetabisulfite 15.88 Sodium tetraborate pentahydrate 11.18 Aluminumsulfate (18.5 wt. %) 36.26

TABLE V Conductivity Enhancement Solution Component Amount (g/liter)[1,2-Bis(3-aminopropropylamino)- 11.15 ethane] Triethanolamine (99 wt.%) 38.6 Triethanolamine hydrochloride 14.0 Dimethylaminoborane 12.0Sodium lauryl sulfate 0.030 2,2-Bipyridine 1.00

TABLE VI Stabilizer Solution Component Amount (g/liter) Sodium hydroxide(50 wt. %) 0.29 N-[3-(2,5-dihydro-5-thioxo-1H- 0.82tetrazol-1-yl)phenyl]acetamide

Other electrically-conductive articles can be similarly prepared from aconductive film element precursor that differs from those describedabove only in the composition of the hydrophilic overcoat layer that canbe as follows:

488 mg/m² of gelatin, 6 mg/m² of 0.6 μm insoluble polymeric matteparticles, 20 mg/m² of a silver halide emulsion having a composition of98 mol % silver chloride and 2 mol % silver iodide (emulsion grainshaving rounded cubic morphology and an edge length 0.36 μm), 25 mg/m² ofTINUVIN® 328 UV radiation absorber, and conventional surfactants.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

PARTS LIST

-   5 Electrically-conductive article-   8 Electrically-conductive silver connector wire pattern-   10 Silver main wire-   15 Portion of photosensitive silver halide emulsion layer-   20 Silver micro-wire-   22 Silver end wire-   24 Silver cross wire-   40 Transparent substrate-   42 First supporting side (of transparent substrate)-   44 Opposing second supporting side (or transparent substrate)-   50 Transparent region(s)-   60 Non-exposed and non-developed silver halide grains-   62 Silver metal particles-   64 Hydrophilic binder-   100 Conductive film element precursor provided-   105 Conductive film element precursor imagewise exposed-   107 Imagewise exposure of first side of conductive film element    precursor-   109 Imagewise exposure of second side of conductive film element    precursor-   110 Exposed conductive film element developed-   112 Development of first side of imagewise exposed precursor-   114 Development of second side of imagewise exposed precursor-   D1 Silver micro-wire maximum height-   D2 Silver micro-wire minimum height-   L Silver micro-wire length-   S1 Distance between adjacent silver main wires-   S2 Distance between adjacent silver micro-wires-   W Silver micro-wire width

The invention claimed is:
 1. A method for providing anelectrically-conductive article using photosensitive silver halide, themethod comprising: imagewise exposing a conductive film elementprecursor that comprises a transparent substrate comprising a firstsupporting side and an opposing second supporting side and aphotosensitive silver halide emulsion layer on at least the firstsupporting side, to radiation to provide, in the photosensitive silverhalide emulsion layer on at least the first supporting side: (a) alatent electrically-conductive silver metal electrode grid, (b) a latentelectrically-conductive silver connector wire pattern different from thelatent electrically-conductive silver metal electrode grid, andoptionally, (c) transparent regions outside of both the latentelectrically-conductive silver metal electrode grid and the latentelectrically-conductive silver connector wire pattern; and processingthe latent electrically-conductive silver metal electrode grid and thelatent electrically-conductive silver connector wire pattern using atleast solution physical development and silver halide fixing, toprovide: (a) an electrically-conductive silver metal electrode grid fromthe latent electrically-conductive silver metal electrode grid, (b) anelectrically-conductive silver connector wire pattern from the latentelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the electrically-conductivesilver metal electrode grid and the electrically-conductive silverconnector wire pattern, wherein: (i) the electrically-conductive silverconnector wire pattern comprises at least one silver main wire thatcomprises two or more silver micro-wires that are electrically connectedto a silver end wire at an end of the at least one silver main wire, thetwo or more silver micro-wires and the silver end wire in the at leastone silver main wire forming a bundled pattern; (ii) the average lengthof each silver micro-wire is at least 1 mm; (iii) the ratio of theaverage width of each silver micro-wire to the average distance betweentwo adjacent silver micro-wires in each bundled pattern is at least0.5:1 but less than 2:1; (iv) the electrically-conductive silverconnector wire pattern has an integrated transmittance of less than 68%;and (v) for each silver micro-wire, the ratio of maximum height tominimum height is at least 1.05:1.
 2. The method of claim 1, wherein theelectrically-conductive silver connector wire pattern comprises at leasttwo adjacent silver main wires, and the average distance between the atleast two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.
 3. The method of claim 2, wherein the average distance betweenany two adjacent silver micro-wires in each bundled pattern is at least2 μm and up to and including 10 μm.
 4. The method of claim 1, whereinthe conductive film element precursor further comprises a photosensitivesilver halide emulsion layer disposed on the opposing second supportingside of the transparent substrate, and the method further comprising:imagewise exposing the photosensitive silver halide emulsion layer onthe opposing second supporting side of the transparent substrate toprovide (a) an opposing latent electrically-conductive silver metalelectrode grid, (b) an opposing latent electrically-conductive silverconnector wire pattern different from the opposing latentelectrically-conductive silver metal electrode grid, and optionally, (c)transparent regions outside of both the opposing latentelectrically-conductive silver metal electrode grid and the opposinglatent electrically-conductive silver connector wire pattern; andprocessing the opposing latent electrically-conductive silver metalelectrode grid and the opposing latent electrically-conductive silverconnector wire pattern using at least solution physical development andsilver halide fixing, to provide: (a) an opposingelectrically-conductive silver metal electrode grid from the opposinglatent electrically-conductive silver metal electrode grid, (b) anopposing electrically-conductive silver connector wire pattern from theopposing latent electrically-conductive silver connector wire pattern,and optionally, (c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern on the opposingsecond supporting side of the transparent substrate, wherein, on theopposing second supporting side of the transparent substrate: (i) theopposing electrically-conductive silver connector wire pattern comprisesat least one silver main wire that comprises two or more silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern; (ii) the average length of each silvermicro-wire is at least 1 mm; (iii) the ratio of the average width ofeach silver micro-wire to the average distance between two adjacentsilver micro-wires in each bundled pattern is at least 0.5:1 but lessthan 2:1; (iv) the opposing electrically-conductive silver connectorwire pattern has an integrated transmittance of less than 68%; and (v)for each silver micro-wire, the ratio of maximum height to minimumheight is at least 1.05:1.
 5. The method of claim 4, wherein theopposing electrically-conductive silver connector wire pattern comprisesat least two adjacent silver main wires, and the average distancebetween the at least two adjacent silver main wires is greater than theaverage distance between any two adjacent silver micro-wires in eachbundled pattern.
 6. The method of claim 4, wherein the average distancebetween any two adjacent silver micro-wires in each bundled pattern onthe opposing second supporting side of the transparent substrate is atleast 2 μm and up to and including 10 μm.
 7. The method of claim 4,wherein imagewise exposing and processing of the photosensitive silverhalide emulsion layer on the opposing second supporting side of thetransparent substrate are carried out simultaneously with imagewiseexposing and processing of the photosensitive silver halide emulsionlayer on the first supporting side of the transparent substrate.
 8. Themethod of claim 1, wherein for each silver micro-wire, the ratio ofmaximum height to minimum height is at least 1.1:1.
 9. The method ofclaim 1, wherein at least one silver micro-wire has a maximum heightthat is the same as its center height.
 10. The method of claim 1,wherein at least one silver micro-wire has a maximum height that iscloser to its outer edge than to its center height.
 11. The method ofclaim 1, wherein each silver micro-wire has a ratio of maximum height toaverage height of at least 1.05:1.
 12. The method of claim 1, whereinthe average width of each silver micro-wire is at least 5 μm and up toand including 20 μm.
 13. The method of claim 1, wherein each bundledpattern comprises at least one silver cross-wire between adjacent silvermicro-wires that is not at the end of the adjacent silver micro-wires.14. The method of claim 1, wherein each bundled pattern comprisesmultiple silver cross-wires between adjacent silver micro-wires, whereinthe multiple silver cross-wires are arranged at a distance from eachother of at least 100 μm.
 15. The method of claim 1, wherein eachbundled pattern comprises multiple silver cross-wires in a set ofadjacent silver micro-wires that are offset from multiple silvercross-wires in an adjacent set of adjacent silver micro-wires.
 16. Themethod of claim 14, wherein each of the multiple silver cross-wires issubstantially perpendicular to the adjacent silver micro-wires.
 17. Themethod of claim 1, wherein the average distance between any two adjacentsilver main wires is greater than the average distance between any twoadjacent silver micro-wires in each bundled pattern by at least 30%. 18.The method of claim 1, wherein the ratio of the average width of eachsilver micro-wire to the average distance between two adjacent silvermicro-wires in each bundled pattern is at least 1:1 and up to andincluding 2:1.
 19. The method of claim 1, wherein theelectrically-conductive silver connector wire pattern has an integratedtransmittance of less than 50% and the electrically-conductive silvermetal electrode grid has an integrated transmittance of at least 90%.20. The method of claim 4, wherein the opposing electrically-conductivesilver connector wire pattern has an integrated transmittance of lessthan 50% and the opposing electrically-conductive silver metal electrodegrid has an integrated transmittance of at least 90%.